Storms Are Hitting California. Please Remain Calm.
The past few days have seen a relative barrage of storms sweep across drought-parched California, bringing rain and snow such as the state hasn’t seen in years.
It’s a welcome sight, to be sure. But don’t let the headlines make you complacent about the drought.
“California Snowpack Exceeds Average for First Time in Years,” says the L.A. Times.
“Calif. Storms Produce Above-Average Snowpack,” says Capital Press.
“California Snowpack Measures an Encouraging 111% of Normal,” says the Riverside Press-Enterprise.
And so it goes.
Californians have a short memory about weather. So let’s rewind a bit.
The state is in a drought because the month of January has proved to be a dud, precipitation wise, in several of the past few years. This was especially true in 2015, when January proved to be the driest in recorded history — after a wet December.
Why is January so important? Historically, it tends to be the wettest month of the year in California. This is especially important for something called the 8-Station Index, a measurement by the California Department of Water Resources that records precipitation in the state’s most important watershed, the Northern Sierra Nevada. It’s the most important because it fills the state’s largest and most strategic reservoirs, including Shasta and Oroville. Since 1922, on average, January has been the wettest month for the 8-Station Index.
In short, if California loses out on January precipitiaiton, drought is likely.
So while December precipitation is great, and while it helps the mountain ski resort economy immensely, we can’t begin to speculate about drought until January precipitation numbers are known. That is especially true after the way January has performed in recent years.
“Unfortunately it seems like it’s a trend in the last three or four years, that January’s just been a dud,” Dave Rizzardo, chief of snow surveys at DWR, told Capital Public Radio on Jan. 29 this year.
Numerous California reservoirs saw big inflows as a result of recent storms. And that’s good. But let’s not lose track of how far they have to go. For instance, although Folsom Reservoir saw a nice increase of 45,000 acre-feet (55,000,000 cubic meters) in recent days from stormwater runoff, it is still at only 19 percent of capacity. Many more storms are needed.
So it’s important not to get too excited by headlines like this:
“Tahoe Gets 6.4 Billion Gallons of Water in 24 hrs.,” proclaims The San Francisco Chronicle.
Sounds like a lot of water, doesn’t it? Actually, it’s only about 19,000 acre-feet (23,000,000 cubic meters). That’s enough to meet the water needs of about 40,000 average California households for a year, which is important. But it’s only one one-hundredth of a percent of Lake Tahoe’s total capacity.
And while those storms have raised Tahoe’s water level by just under 2in (5cm), that still isn’t enough to return the lake to its natural rim, where water could resume flowing into the Truckee River for the first time since October 2014.
On the bright side, another fast-moving winter storm is expected to sweep across California on Thursday, blanketing the Sierra Nevada in more snow for Christmas Eve. A winter storm warning is in effect across the mountains through early Friday morning. Up to 2ft (60cm) of new snow is expected at Trans-Sierra highway passes, and as much as 8in (20cm) down to the 3,000ft (900m) elevation.
But just like in recent winters, the New Year could start out dry once again. A new two-week forecast issued Tuesday by the National Weather Service Climate Prediction Center favors dry conditions across Northern California through Jan. 5.
Top image: Squaw Valley Ski Resort at Lake Tahoe on Tuesday reported getting 3ft (90cm) of snow in 24 hours. (Squaw Valley Ski Resort)